Auxiliary power plant for aircraft



March 22, 193a.

W. R. COOL v AUXILIARY POWER PLANT FOR AIRCRAFT File d Jpne 20, 1935 E:=======EE= 22255:: Q N

m mm Patented Mar. 22, 1938 cries AUXILIARY POWER PLAN T FOR AIRCRAFT William Randolph Cool, Coraopolis, Pa., assignor to W. T. Tredway, trustee Application June 20,

1 Claim.

This invention relates to improvements in aircraft, and the primary object of the invention is to provide a safety factor for power driven aircraft in the nature of an attachment that gives a short, auxiliary, flying range in event of failure of the power plant.

Another object of the invention is to provide an airplane with an auxiliary power plant that may be utilized to propel the airplane in event of failure of the main power plant.

Still another object of the invention is to provide an airplane with an auxiliary power plant comprising a spring motor containing sufficient stored mechanical energy to propel the airplane a limited distance.

A further object of the invention is to provide an airplane with a main power plant and an auxiliary power plant and a mechanism to disconnect the main power plant in event of failure thereof and connect the auxiliary power plant.

Other objects will be apparent, from the description, to those skilled in the art. The present disclosure constitutes an exposition of an embodiment of the invention, and illustrates the best means I have thus far devised for reducing the invention to practice. It is to be understood that the structural details shown and described shall not constitute limitations inconsistent with the scope of the invention as claimed.

In the drawing:

Figure 1 is a partial vertical section of the front portion of an airplane showing my invention applied thereto.

Figure 2 is a fragmentary elevation of the lock for the spring motor.

Figure 3 is a section on the line 3-3 of Figure 2.

In power driven aircraft one of the chief reasons for accidents is the' failure of the power plant. rain and weather, in the event of such an occurrence the safety factor is dependent upon the altitude. At other critical periods of flight the failure of the power plant usually results in a crack-up of the aircraft. I propose toovercome this hazard as far as possible by providing an auxiliary power plant in the nature of a spring motor thatis capable of propelling the 1 aircraft a limited distance so as to enable the pilot to select a suitable emergency landing site, or provide temporary propulsion at a critical period.

In the form of the invention shown, I indicates the front portion of an airplane having a wing structure 2, pilot seat 3, landing gear 4, and

Even under favorable conditions of ter- 1935, Serial No. 27,595

hood 5. Within the hood is mounted the main motor l2 mounted within the hood 5, adjacent the engine 6. The spring motor comprises the usual spiral spring I3, mounted on a center shaft l4, extending parallel with the drive shaft 7, and terminating further forward in the hood adjacent the nose portion of the airplane.

V The shaft I4 is mounted in a front bracket l5 and a rear bracket IS. A ratchet wheel I? and locking pawl H3, at the rear end of the shaft, hold the motor under tension when wound. The front end of the shaft is flat sided, as shown at IQ, for the reception of cranking means, not shown, insertable through an opening in the nose portion of the hood, normally covered by a plate 2!], to wind the motor when necessary.

The spring motor is capable of operative connection with the driven shaft 8 through the medium of a long pinion 2! mounted in a stub shaft on the bracket l5 and meshing with a gear 22 adjacent the front end of the spring motor shaft M. The pinion 2! also meshes with a gear 23 slidably mounted on the driven shaft 8 and carrying a clutch face 24 at the front side thereof and a clutch collar 25 at the rear side thereof. A cooperating clutch face 26 is rigidly connected to the shaft 8. Upon engagement of the clutch faces bya means to be hereinafter described, a driving connection between the spring motor and driven shaft is provided, and consequently the propeller I!) may be driven by the spring motor.

To provide a means for disengaging the main power plant and simultaneously engaging the auxiliary power plant I provide an operating rod 21, extending parallel with the spring motor shaft M and capable of manual longitudinal movement. The front of said rod is supported by a hanger 28 dependent from the cross strut H, and its rear portion extends through the bracket l6 and partition 29, terminating in a handle portion 30. The front end of said rod has a forked engagement with the clutch collar 25. An inclined faced nib 3| is cooperatively engaged with a pivoted fork 32 V of the collar on the clutch 9. The pawl I8 is also mounted on said rod through the medium of a two-part connected collar 33, as best illustrated in Figure 3.

It is apparent that with the parts disposed as shown in Figure 1 the airplane is propelled by the main power plant or engine 6, drive shaft 1, normally engaged clutch 9, driven shaft 8 and propeller Ill. The spring motor is wound. but held inoperative by the locking pawl l8, and as the clutch faces 24 and 28 are disengaged there is no connection to the driven shaft 8.

Should for any reason the main power plant or engine 6 fail to function, the pilot merely has to grasp the handle 30 of the rod 2'! and push the same forward. This simultaneously engages the clutch faces 24 and 26, disengages the main power clutch 9, and releases the pawl I8 from the ratchet wheel H. The auxiliary power plant then functions by action of the spring l3 rotating the shaft 14 and, through the gear train 22, 2| and 23 and clutch faces 24 and 26, power is transmitted to the shaft 8 to drive the propeller It]. At the same time the retarding action of the dead engine 6 is relieved by the operation of the clutch 9 to disconnect the shafts l and 8.

The auxiliary spring motor I2 is of sufficient strength to store enough mechanical energy to drive the propeller to give the airplane a limited flying range in the event of the failure of the main power plant. The spring motor structure may be relatively light as it is not contemplated that the auxiliary power plant will furnish energy for sustained flight but merely to give the pilot power control of the airplane in an emergency of the character outlined.

I claim:

In an airplane, a propeller, a propeller shaft, a main power plant for normally driving the same, an auxiliary power plant including a wound spring motor having a ratchet wheel, means for simultaneously disconnecting the main power plant from the propeller shaft and connecting the auxiliary power plant thereto, said means including a manually operable shaft, and a locking pawl on said shaft normally engaging the ratchet wheel of the spring motor and releasable therefrom upon operation of the shaft to immediately place the auxiliary power plant in operation.

WILLIAM RANDOLPH COOL. 

